About this calculator

401(k) Calculator

Project your 401(k) growth with employer match, then simulate retirement withdrawals over time.

What it does

Projects the future value of your 401(k) account by compounding your current balance, adding annual employee contributions, and applying any employer match at your expected rate of return. A separate withdrawal mode estimates how long your savings could last in retirement with annual distributions.

Who it is for

Employees contributing to a 401(k), especially people with an employer match. It is also useful for anyone planning retirement withdrawals, comparing contribution rates, or testing how much balance they need to reach a target retirement age.

How it works

In growth mode, the calculator starts with the opening balance, applies one annual return, adds your employee contribution, and then adds the employer match if enabled. The match uses your contribution percent up to the salary cap percent, then multiplies that eligible slice by the match percent. In withdrawal mode, the calculator starts with your retirement balance, applies annual growth, subtracts the planned withdrawal, and repeats until age 100 or depletion.

Limitations

Does not model taxes, early withdrawal penalties, required minimum distributions (RMDs), contribution limits, vesting schedules, fees, raises, or changing contribution rates. Market returns are assumed constant each year, which never happens in reality.

Key formulas

Future Value with Match
Each year the account grows by the return, then contributions and match are added. balance = prevBalance × (1 + return) + employeeContribution + employerMatch
Employer Match
The match applies to a capped percentage of salary. matchAmount = min(employeeContribution, salary × matchCap%) × matchRate%. Any contribution above the cap is not matched.
Withdrawal Projection
Each year the balance grows, then the withdrawal is subtracted. balance = prevBalance × (1 + return) − withdrawalAmount. Repeats until age 100 or depletion.
Employee Contribution
Based on your salary and contribution percentage. employeeContribution = salary × contributionPercent / 100

Early withdrawal

401(k) Early Withdrawal: the 10% Penalty and Tax

Withdrawing from a 401(k) before age 59½ usually triggers an additional 10% early-withdrawal penalty on top of ordinary income tax on the amount withdrawn. This section explains how the penalty and tax work and when exceptions may apply.

The 10% early-withdrawal penalty

The IRS imposes an additional 10% tax on most distributions taken before age 59½, unless an exception applies. The penalty applies to the amount distributed — both your contributions and the earnings on them — and is paid in addition to any income tax due.

Income tax on the distribution

A traditional 401(k) distribution is taxable as ordinary income in the year you receive it. Your marginal tax bracket determines the rate, so a $10,000 withdrawal could be reduced by income tax plus the 10% penalty before you see the cash.

Example: a $10,000 early withdrawal

With a 22% federal marginal rate, a $10,000 early withdrawal loses $2,200 to income tax and $1,000 to the early-withdrawal penalty, leaving about $6,800 — before any state tax.

Exceptions to the 10% penalty

Exceptions include unreimbursed medical expenses, disability, a qualified first-time home purchase (up to $10,000), substantially equal periodic payments (72(t)), certain military reservist distributions, and separation from service at age 55 or later.

State taxes

Most states also tax the distribution, and a few add their own early-withdrawal penalty. Check your state's rules for the full picture.

Before taking an early 401(k) withdrawal, estimate the combined tax and penalty impact — the calculator above shows your balance, but the actual cash you receive will be lower.

How to use it

  1. 1
    Choose growth or withdrawal modeGrowth mode projects your balance from today to retirement. Withdrawal mode simulates how long your savings last once you start taking distributions.
  2. 2
    Enter your current detailsInput your current age, current 401(k) balance, annual salary, and expected annual return rate.
  3. 3
    Set your contribution rateEnter the percentage of your salary you contribute each year. The calculator applies this to your annual salary.
  4. 4
    Configure employer matchToggle the employer match on and enter your plan's match percent and salary cap percent. The match is calculated using the standard plan formula.
  5. 5
    Review growth projectionsThe calculator shows a year-by-year table of your projected balance, contributions, match, and earnings out to age 100.
  6. 6
    Test withdrawal scenariosSwitch to withdrawal mode and enter a planned annual withdrawal to see how long your projected balance might last in retirement.
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